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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 * may be used to endorse or promote products derived from this software without
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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package org.hisp.dhis.db.migration.v35;

import static org.hisp.dhis.trackedentity.TrackedEntityAttributeService.TEA_VALUE_MAX_LENGTH;

import java.sql.SQLException;
import java.sql.Statement;
import org.flywaydb.core.api.migration.BaseJavaMigration;
import org.flywaydb.core.api.migration.Context;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This Java migration changes the data type of the 'value' column in trackedentityattributevalue
 * table to varchar(1200). Additionally we put a btree index on the same table, to improve
 * performance of lookup. This upograde will fail is any value in the table exceeds 1200 characters.
 * Due to this, we catch any SQLException and write a custom message, including a link to a
 * community.dhis2.org post explaining this upgrade, and how to deal with any upgrade failures.
 *
 * <p>By setting canExecuteInTransaction to false, we let this upgrade run outside the main flow of
 * flyway, allowing us to ignore that the upgrade potentially fails.
 *
 * @author Stian
 */
public class V2_35_1__Add_teav_btree_index extends BaseJavaMigration {
  private static final String COP_POST_URL =
      "https://community.dhis2.org/t/important-database-upgrade-for-tracker-performance/38766";

  private static final Logger log = LoggerFactory.getLogger(V2_35_1__Add_teav_btree_index.class);

  @Override
  public void migrate(Context context) {

    try (Statement statement = context.getConnection().createStatement()) {
      statement.execute(
          "alter table trackedentityattributevalue alter column value set data type varchar(1200)");
      statement.execute(
          "create index in_trackedentity_attribute_value on trackedentityattributevalue using btree (trackedentityattributeid, lower(value)) ");
    } catch (SQLException e) {
      String message =
          "Could not perform upgrade of table 'trackedentityattributevalue'. "
              + String.format(
                  "Column 'value' should be altered to data type varchar(%s) and receive a new index. ",
                  TEA_VALUE_MAX_LENGTH)
              + String.format(
                  "For more information, please see the following post: '%s'. ", COP_POST_URL)
              + String.format("Error message was: %s", e.getMessage());

      log.warn(message);
    }
  }

  @Override
  public boolean canExecuteInTransaction() {
    return false;
  }
}
